Dalen-Kjørholt Gruve

Dalen-Kjørholt Mine

Useful Information

Location:	Kjørholt, Brevik, Porsgrunn.
Open:	closed. [2026]
Fee:	closed. [2026]
Classification:	Limestone Mine, underground mine.
Light:	Electric Light
Dimension:
Guided tours:	D=2 h.
Photography:
Accessibility:
Bibliography:	F. S. Nordrum (1993): Die Dalen-Kjörholt-Kalksteingrube in S-Norwegen, ein neuer Fundort für exzellente Calcitstufen Min.-Welt, Jg.4, Nr.5, S.49-56. F. S. Nordrum (2008) Neuer Calcit-Fund aus Dalen-Kjörholt/ Norwegen Min.-Welt, Jg.19, Nr.2, S.32-33.
Address:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1916	Dalen mine opened.
1929	Kjørholt mine opened.
1933	Kjørholt mine switched to underground mining.
1955	quarry established at Bjørntvet, 7 km from Dalen, limestone transported by cable car.
1960	begin of underground quarrying at Dalen.
1975	begin of transport by rail.
1976	underground connection of Dalen and Kjørholt mine.
1988	Norcem purchases Kjørholt mines from Norsk Hydro.

Geology

The limestone deposit is about 40 meters thick and slopes about 15 degrees down towards the Eidangerfjord.

Description

The Dalen-Kjørholt Gruve is the largest underground limestone mine in the world. Even more important is the fact, that it is producing one million tons of top quality limestone, which is processed into cement for the European and world wide markets. However, its fame is based on the calcite minerals found here. Frequent small caves contain abundant varieties of calcite crystals. Common are the rare double terminated crystals. The variety of habits and colour, and the perfection of crystallization are extraordinary.

This mine is quite exceptional, as it mines the limestone underground. Normally limestone is not valuable enough to make underground mining profitable, but limestone deposits are quite rare in Norway. So when most of the surface limestone was mined the underground mining became quite important. Today the Dalen mines have 250 km of passages and extend 340 m below sea level and underneath the fjord.

The mine was operated by Norcem AS, a company which was strongly committed to the preservation of significant mineralogical finds. Gunnar Jenssen had the job is to collect specimens before they are lost to the mining operation. His finds were on display at the mineral museum of the company, other items are sold. Several crystal lined caverns in the mine are preserved for their intrinsic beauty. We listed this site in [2005], when visits of Brevik were quite difficult as it was an operating mine. As a compromise Norcem offered some scheduled visits on six Thursday during July. Buses started at Brevik cinema, the number of visitor was restricted to 50 on each tour.

Unfortunately the visits were discontinued, we were not able to get any information on tours. Also, the mineral museum seems to be closed. As far as we know the items were transferred to the Natural History Museum in Oslo in 2024. The limestone mine is still in operation, the new owner is Heidelberg Materials Sement Norge AS from Germany. They produce cement with the world’s first full-scale carbon capture facility, in other words the carbon dioxide emissions are significantly reduced. But on the other side it seems they discontinued any tours.